Lower units need gear lubricant just like any other metal-to-metal surface in your power train. And while boaters typically pay some attention to the motor oil they buy, few pay much attention to the gear lube oil. For most people it’s just another necessary expense, and it is given little thought. But just as synthetic motor oil improves performance for engines, so, too, does synthetic gear oil make lower units run quieter, cooler, smoother and have a longer life. The folks at Royal Purple tell us that their “Max-Gear” lube oil “provides unsurpassed protection to heavily loaded gears” because it is synthetic and as their proprietary additive “Synslide.”
According to the chemists and engineers at Royal Purple, “Max-Gear” outperforms other gear oils because it combines the highest quality synthetic oils with Royal Purple’s proprietary Synslide additive technology."
What is the “Synslide” Additive?
Royal Purple explains: “Synslide additive technology, Royal Purple's tough, EP lubricating film, provides maximum protection under boundary lubrication conditions typically caused by heavily loaded, slow speed and / or shock load conditions. This tenacious, slippery film significantly improves lubrication and reduces wear by increasing the oil film thickness and toughness, which helps to prevent metal-to-metal contact in gears and bearings.
“Synslide additive technology is noncorrosive to gears and bearings, including case-hardened gears that are easily pitted by conventional sulfur-phosphorus EP oils. Synslide additive technology displaces water from metal surfaces and excels in protecting equipment in wet environments. It also fortifies the oil against the detrimental effects of heat, which causes oil to oxidize.”
Royal Purple Website –